llvm-project/clang/lib/AST/ItaniumCXXABI.cpp

79 lines
2.4 KiB
C++

//===------- ItaniumCXXABI.cpp - AST support for the Itanium C++ ABI ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This provides C++ AST support targeting the Itanium C++ ABI, which is
// documented at:
// http://www.codesourcery.com/public/cxx-abi/abi.html
// http://www.codesourcery.com/public/cxx-abi/abi-eh.html
//
// It also supports the closely-related ARM C++ ABI, documented at:
// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf
//
//===----------------------------------------------------------------------===//
#include "CXXABI.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/Type.h"
#include "clang/Basic/TargetInfo.h"
using namespace clang;
namespace {
class ItaniumCXXABI : public CXXABI {
protected:
ASTContext &Context;
public:
ItaniumCXXABI(ASTContext &Ctx) : Context(Ctx) { }
std::pair<uint64_t, unsigned>
getMemberPointerWidthAndAlign(const MemberPointerType *MPT) const {
const TargetInfo &Target = Context.getTargetInfo();
TargetInfo::IntType PtrDiff = Target.getPtrDiffType(0);
uint64_t Width = Target.getTypeWidth(PtrDiff);
unsigned Align = Target.getTypeAlign(PtrDiff);
if (MPT->getPointeeType()->isFunctionType())
Width = 2 * Width;
return std::make_pair(Width, Align);
}
CallingConv getDefaultMethodCallConv(bool isVariadic) const {
return CC_C;
}
// We cheat and just check that the class has a vtable pointer, and that it's
// only big enough to have a vtable pointer and nothing more (or less).
bool isNearlyEmpty(const CXXRecordDecl *RD) const {
// Check that the class has a vtable pointer.
if (!RD->isDynamicClass())
return false;
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
CharUnits PointerSize =
Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
return Layout.getNonVirtualSize() == PointerSize;
}
};
class ARMCXXABI : public ItaniumCXXABI {
public:
ARMCXXABI(ASTContext &Ctx) : ItaniumCXXABI(Ctx) { }
};
}
CXXABI *clang::CreateItaniumCXXABI(ASTContext &Ctx) {
return new ItaniumCXXABI(Ctx);
}
CXXABI *clang::CreateARMCXXABI(ASTContext &Ctx) {
return new ARMCXXABI(Ctx);
}